add test for bug in git-mv for recursive submodules

When using git-mv with a submodule it will detect that and update the
paths for its configurations (.gitmodules, worktree and gitfile). This
does not work for recursive submodules where a user renames the root
submodule.

We discovered this fact when working on on-demand fetch for renamed
submodules. Lets add a test to document.

Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: hvoigt

t/t7001-mv.sh

@@ -491,4 +491,29 @@ test_expect_success 'moving a submodule in nested directories' '
 	test_cmp actual expect
 '
 
+test_expect_failure 'moving nested submodules' '
+	git commit -am "cleanup commit" &&
+	mkdir sub_nested_nested &&
+	(cd sub_nested_nested &&
+		touch nested_level2 &&
+		git init &&
+		git add . &&
+		git commit -m "nested level 2"
+	) &&
+	mkdir sub_nested &&
+	(cd sub_nested &&
+		touch nested_level1 &&
+		git init &&
+		git add . &&
+		git commit -m "nested level 1"
+		git submodule add ../sub_nested_nested &&
+		git commit -m "add nested level 2"
+	) &&
+	git submodule add ./sub_nested nested_move &&
+	git commit -m "add nested_move" &&
+	git submodule update --init --recursive &&
+	git mv nested_move sub_nested_moved &&
+	git status
+'
+
 test_done